feat: Jujutsu VCS (jj) widgets

[dancorreia-swe]

Summary

• Add Jujutsu (jj) VCS support with 5 new widgets mirroring the existing Git widget set
• New widgets: JJ Bookmarks, JJ Workspace, JJ Root Dir, JJ Changes, and JJ Revision
• New src/utils/jj.ts utility module with runJj() and isInsideJjRepo() helpers
• All widgets registered under a new "Jujutsu" category in the TUI catalog, grouped after Git

edit: correct the jj commands that were changed

Config:

In use:

New Widgets

Widget	Type	Description	jj Command
JJ Bookmarks	jj-bookmarks	Bookmark(s) at current change	jj log --no-graph -r \'heads(::@ & bookmarks())\' --template bookmarks
JJ Workspace	jj-workspace	Active workspace name	jj workspace list
JJ Root Dir	jj-root-dir	Repository root directory name	jj root
JJ Changes	jj-changes	Insertions/deletions count	jj diff --stat
JJ Revision	jj-revision	Current change ID (short)	jj log --no-graph -r @ -T 'change_id.shortest()'